The pair began dating in early 2010, shortly after she split from husband Deryck Whibley of Sum 41.
A source told Life & Style that the main reason behind the split was down to a disagreement over marriage beliefs.
"They decided to end their relationship," the insider said. "It wasn't working out, and they wanted to go their separate ways."
"She wanted to settle down, but he wasn't exactly ready," a separate source explained. "They had been having problems starting in the summer with her tour because she was on the road all the time.
"It put a strain on their relationship."
Lavigne and Jenner were involved in a Hollywood brawl in November, where the former Hills star was reportedly hit in the head with a bottle.
Watch the video for Avril Lavigne's 'Wish You Were Here' below: